/*
 * File    : PRUDPPacketHandlerRequest.java
 * Created : 20-Jan-2004
 * By      : parg
 * 
 * Azureus - a Java Bittorrent client
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details ( see the LICENSE file ).
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package com.aelitis.net.udp.uc.impl;

/**
 * @author parg
 *
 */

import java.net.InetSocketAddress;

import org.gudy.azureus2.core3.util.AESemaphore;
import org.gudy.azureus2.core3.util.SystemTime;

import com.aelitis.net.udp.uc.PRUDPPacket;
import com.aelitis.net.udp.uc.PRUDPPacketHandlerException;
import com.aelitis.net.udp.uc.PRUDPPacketHandlerRequest;
import com.aelitis.net.udp.uc.PRUDPPacketReceiver;

public class PRUDPPacketHandlerRequestImpl implements PRUDPPacketHandlerRequest {
    private AESemaphore sem = new AESemaphore("PRUDPPacketHandlerRequest");

    private long timeout;
    private PRUDPPacketReceiver receiver;

    private PRUDPPacketHandlerException exception;
    private PRUDPPacket reply;

    private long send_time;
    private long reply_time;

    protected PRUDPPacketHandlerRequestImpl(PRUDPPacketReceiver _receiver, long _timeout) {
        receiver = _receiver;
        timeout = _timeout;
    }

    protected void sent() {
        send_time = SystemTime.getCurrentTime();
    }

    protected long getSendTime() {
        return (send_time);
    }

    protected long getTimeout() {
        return (timeout);
    }

    public long getElapsedTime() {
        if (send_time == 0 || reply_time == 0) {

            return (-1);
        }

        long res = reply_time - send_time;

        if (res < 0) {

            res = 0;
        }

        // do something sensible with 0 time!

        if (res == 0) {

            res = SystemTime.TIME_GRANULARITY_MILLIS / 2;
        }

        return (res);
    }

    protected void setReply(PRUDPPacket packet, InetSocketAddress originator, long receive_time) {
        if (reply == null) {

            reply_time = receive_time;

            reply = packet;

        } else {

            packet.setPreviousPacket(reply);

            reply = packet;
        }

        if (!packet.hasContinuation()) {

            sem.release();
        }

        if (receiver != null) {

            receiver.packetReceived(this, packet, originator);
        }
    }

    protected void setException(PRUDPPacketHandlerException e) {
        // don't override existing reply for synchronous callers as they can
        // do what they want with it

        if (reply == null) {

            reply_time = SystemTime.getCurrentTime();

            exception = e;
        }

        sem.release();

        // still report errors to asyn clients (even when a reply has been received)
        // as they need something to indicate that a continuation packet wasn't received
        // and that the request has timed-out. ie. a multi-packet reply must terminate
        // either with the reception of a non-continuation (i.e. last) packet *or* a
        // timeout/error

        if (receiver != null) {

            receiver.error(e);
        }
    }

    protected PRUDPPacket getReply()

    throws PRUDPPacketHandlerException {
        sem.reserve();

        if (exception != null) {

            throw (exception);
        }

        return (reply);
    }
}
